The term “sheet pack” originally referred to a procedure where a bed sheet soaked with water was wrapped around a person's body. While the body gradually warmed the sheet the supposedly agitated person was comforted by the warmth and cocoon of surrounding fabric.
Today the term has a broader meaning, and in the beauty industry refers to various sizes and shapes of fabric impregnated with skin treatment compositions for temporary application to skin to provide immediate benefits. Interestingly enough, the comfort aspect of the original sheet packs remains, since today's products are typically used during quiet and restful times of the day or at night. In most cases, today's sheet packs are for facial treatment. They are applied to the face and removed after a short period of time which may range from 1 to 30 minutes. Thereafter the face can either be cleansed or, if appropriate, any treatment composition remaining on the skin is rubbed into the skin. These sheet packs are particularly popular with Asian consumers and sometimes contain active ingredients in larger concentrations than what is found in the creams and lotions typically used as part of the day to day beauty routine.
However, most sheet packs today are formulated with a “kitchen sink” approach and contain many different active ingredients that are touted to have a variety of benefits. There is a failure to appreciate the difference between a treatment benefit and the timing of that treatment benefit in order to maximize efficacy. For example, it is known that in native skin cells, expression of different genes is variable over a 24 hour cycle. This is also referred to as circadian rhythms. Skin care products will sometimes contain active ingredients that are said to stimulate or inhibit expression of certain genes to ultimately cause improvement in undesirable skin conditions such as aging, hyper-pigmentation, moisturization, and so on. However, important in maximizing the effectiveness of any treatment composition or the active ingredients therein is timing. In particular, applying the treatment composition to the treatment surface at a time when the treatment surface is optimized to receive it ensures that the treatment itself is maximally effective.
Accordingly, it is an object of the invention to provide a sheet pack with optimized efficacy due to the presence of the sheet pack constituents and a treatment composition that contains at least one active that stimulates expression of a specific gene in skin cells that is normally variably expressed in untreated native skin cells and optionally at least one second skin treatment active ingredient that provides a benefit; and where the sheet pack is applied to the treatment surface (e.g. skin) at a time when the ingredient in the treatment composition that stimulates expression of the specific gene is being maximally expressed in the majority of native untreated skin cells so that the treatment benefit of the ingredient is optimized.